Downregulation of the photosynthetic machinery and carbon storage signaling pathways mediate La2O3 nanoparticle toxicity on radish taproot formation

Zhenggao Xiao; Le Yue; Chuanxi Wang; Feiran Chen; Ying Ding; Yinglin Liu; Xuesong Cao; Zhe Chen; Sergio Rasmann; Zhenyu Wang

doi:10.1016/j.jhazmat.2020.124971

Downregulation of the photosynthetic machinery and carbon storage signaling pathways mediate La₂O₃ nanoparticle toxicity on radish taproot formation

J Hazard Mater. 2021 Jun 5:411:124971. doi: 10.1016/j.jhazmat.2020.124971. Epub 2020 Dec 25.

Authors

Zhenggao Xiao¹, Le Yue¹, Chuanxi Wang¹, Feiran Chen¹, Ying Ding¹, Yinglin Liu¹, Xuesong Cao¹, Zhe Chen², Sergio Rasmann³, Zhenyu Wang⁴

Affiliations

¹ Institute of Environmental Processes and Pollution Control, and School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China.
² Institute of Tropical Fruit Trees, Hainan Academy of Agricultural Science, Haikou 571100, China.
³ Institute of Biology, University of Neuchâtel, Rue-Emile-Argand 11, 2000 Neuchâtel, Switzerland.
⁴ Institute of Environmental Processes and Pollution Control, and School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China. Electronic address: wang0628@jiangnan.edu.cn.

PMID: 33429308
DOI: 10.1016/j.jhazmat.2020.124971

Abstract

The molecular and physiological mechanisms of how rare earth oxide nanoparticles (NPs) alter radish (Raphanus sativus L.) taproot formation and cracking were investigated in the present study. We compared plants that received suspensions of 10, 50, 100, 300 mg L^-1 of La₂O₃ NPs, 300 m L^-1 La₂O₃ bulk-particles (BPs), 0.8 m L^-1 La³⁺, or only water for six days during their tuber formation period. 100 and 300 mg L^-1 La₂O₃ NPs exposure decreased storage root biomass by 38% and 60%, respectively, and they both induced visible root cracking. Physiological analyses showed that La₂O₃ NPs exposure (>100 mg L^-1) significantly inhibited leaf net photosynthetic rate, cell wall pectin synthesis of both storage root epidermis and xylem parenchyma tissues, but increased the contents of cellulose and hemicellulose 1 in root epidermis cell walls. Moreover, transcriptome analysis further found that La₂O₃ NPs changed root cell wall structure by down-regulating core genes involved in cell wall pectin and IAA biosynthesis, which coincided with the observed La₂O₃ NPs-induced root cracking. Our results revealed the molecular mechanisms related to cell wall carbohydrate metabolism in response to NPs stress, providing a step forward for understanding the causes of NPs phytotoxicity on edible plant taproot formation and cracking.

Keywords: Cell wall composition; Lanthanum oxide nanoparticles; Nanotoxicity; Root cracking; Transcriptome.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Carbon
Down-Regulation
Lanthanum
Nanoparticles* / toxicity
Oxides
Plant Roots
Raphanus*

Substances

Oxides
lanthanum oxide
Lanthanum
Carbon